Holding and Rule (Scalia)•The Second Amendment protects an individual right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home.

The handgun ban and the trigger-lock requirement (as applied to self-defense) violate the Second Amendment. The total ban on handgun possession in the home amounts to a prohibition on an entire class of arms that Americans overwhelmingly choose for the lawful purpose of self-defense. This prohibition would fail constitutional muster under any standard of scrutiny. Similarly, the requirement that any lawful firearm in the home be disassembled or bound by a trigger lock makes it impossible for citizens to use arms for the core lawful purpose of self-defense and is therefore unconstitutional.

The Second Amendment right is not a right to keep and carry any weapon in any manner and for any purpose. The Court has upheld gun control legislation including prohibitions on concealed weapons and possession of firearms by felons and the mentally ill, laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, and laws imposing conditions and qualifications on the commercial sale of arms. The historical tradition of prohibiting the carrying of dangerous and unusual weapons supports the holding in United States v. Miller that the sorts of weapons protected are those in common use at the time.